Radio receiving system



Dec. 12, 1950 G. R. P. MARIE 2,533,599 RADIO RECEIVING SYSTEM Filed Feb.18, 1948 7%" :l i/g fla'. 2. a d E IMfENIoR (Ifo/P656 P05527' Pwr/e:MHP/f.

BY i /yZI-TTORNEY v Patented Dec. 12, 1950 .RADILORE'CEIVING SYSTEM:Georges Robert fR-ierre Marl, Paris, France, as-

signor sto Societe Francaise .'Sadir-iCarpentier, a corporation-ofl@rance 'Applicationfebrualjy 18, 1948, jS'erialLNo. V9 ,171

in fFranceMarch 21, 1947 laims. -(Cl. 343510,02)

duced -by a `fgel'ierator ,fare propagated .inside a guiding memberinside which theyessume-a rectilinear polarisation r4to either side @of-two @Quarter Wave devicesincluding'between them azonesubmitted v,to thecontrol of a-.modulator and .wherein they aiSSumefa circular-ermoreeez'lerall-y an elliptic polarisation. Consequently :Said modulationmethod consists -in transform-ing vthe -ivaves lpassontef ethe,generator l`into jtwo Waves :polarised rectilinearly in planesperpendicular t0 Aone an other,-,andrth en:modulating both-wavess toamplitude inza manner such :that `thepealrs of one of said waves Ymaycoincide with -the :minimun-1 values .of fthe other.

,The improvements provided `by the present .invention -nwhileapplyingithefeatures of fthe 'abQVe disclosed modulation allow the execution ofa, receiving ...System wherein .the ,antifading action is independent ofmodulation.

,Such a receiving system is ,of particular advantage with ultra ShortWaves because jitallows inter alia the incorporation of .antifadingmeans Witha verylow time constantso thatiil is rparticularly capable offollowing the niiuctuations 'of the `propagation 'of lsuch Waves.

The invention will now b'e described with further detail 'with referenceto accompanying drawings given `out Aby bway `of mere example withoutany binding sense.

Figs. -1 fan-d V2 are twowiring diagrams V'illustrating `the invention.

In fFig. 1, -I designates -a wave guide, 2 and 2 probes assuming theshape of inner crossedantennae, 3 and 3" coaxialllineelementsfadaptedito connect members 2 -and 12 respectively withfthe two frequency changing devices 4 and .4" for finstance, `thatare:mounted Vin push-pull relationship and fare .submitted :to .the faction-of a esame local oscillator 2,0 fand to 4.Which they are .conneetegd.by ccoaxial line elements d and 5".. Two transformers "6 @and .energize:two amplers f1 and :1' of intermediate freqnency'arrangedfsymmetrically While `8 and =8 Edesignate two -transformers including Leachfthree windings, -9 and 3 being .twO detectors, L0 `and Ii!)twobcafpactiesand lastly ail a resistance.

' series `and -by :the resistance :H

'YIhe system thus constituted :operates as iollows: each :of thefrequency changing devices a4 and 1I produces L"by reasoniof the`antennae 2 and 2 connected therewith and by reason oftheapositionfothelatterinside thelguide `l .airst detection :of the ftworrectilinearly :polar-ised modulated Waves vvthatare .received in saidguide.

:the-primary 6 of `the transformer .is traversed bya-curr ent :proportional Ato (1 ricos-.SID .sin wt @Whereas the r.primary or the"transformer `l' is fed Eby:aicurrentfproportional :to

`(l +1' .cos sinot In fthese formulae, wfdesignateszithe 4pulsai'lionatintermediate frequency, 'Q "the 'pulsa-tion Aat the frequency ofmodulation and 1- the .maximum depthnof modulation.

After amplification ithrough 'the :ampliers and '.'i','.there :isnallyeoollected `on the twolsecondaries faandia vof the `transformerse8andIB induced voltages that iare `added l:to one another and .allow theapplication to `:the idetectors yQ zand 9 in series, ,of a rto'talV:resultant `.voltage fthat iis proportional-:to sin uit.

Last ly,fafter detection-there is collected `at the terminals of theresistance l l a direct ccurrent voltage #that :is v:propertional also`ito :sin wt :and .is therefore :independerrtof fthe tfrequency ofmodulation. Thisololtage is:applicable-for*instance to the grids:controlling :the :amplifiers 1 and f1 that are yprovided 'withelectronic `tubes :of variable slopes and said voltageycontrolsconsequently the antiiadingfaction of the system.

The voltages induced in the two secundarios '8b and b 'of Vthetransformers :e and f8 .are applied in ra .suitable :direction ito :a:second detector or Ito two detectors :3.0 arranged symmetrically awhichdetectoror `detectorsienergise aflowfrequency-a'm- Plerit l..

The `time `constant appearing in 'the operation of fthe iantifadins:means of .above system iS defined hy the capacit-ies :t0 zand Hlinserted in Their qiroducts may abe `\1y =srr1all and the :time constantmay thusbemuch lowerfthanfthe valuesvgenerall-y met with Vvheretofore.

gin the form fof fexecntoniof .fthe invention illustrated :in Eig. l and:described hereinabove, V the diierentymembers :have 1asymmetricalmounting. Said,arrangement.thatfcorresponds-to1a preferred form .of:execution 'is the natural consequence -of the symmetry of the antennae2 andi andiofthe fact of theilatter ,receiving respectively two .wavespolarised at right angles with reference to one another without thislimiting by any means the possibilities of the invention as defined inaccompanying claims.

In particular as concerns the antifading means only, the scope of theinvention is not widened unduly by doing away with the symmetricalarrangement of the elements starting from the output of the frequencychangers 4 and 4' for instance by using a single transformer constitutedby two primaries that are suitably coupled and a single secondary.

The above described symmetrical arrangement ensures an operation that isall the more accurate when the two chains of successive members 2, 3, 4,6, 1,:8 on one hand and 2, 3', 4', B', 1', 8 on the other hand generatein the windings 8a and Ba voltages that are substantially equal inabsolute value. In order to satisfy this condition, it is providedfirstly, according to the invention, to form the resistance l! loadingthe antifading means as .a potentiometer the movable rider of which isconnected with the common point of the windings.

But obviously, the above condition depends above all on the exact phaseshifting between the received waves that are rectilinearly polarisedinside the guiding member i as well as on their maximum respectiveamplitudes. In order to allow a compensation either Vof the relativephase shifting when the polarisation planes are perfectly rectangular,or of the relative amplitude `in the case of an elliptic polarisation orelse of the phase shifting of the whole system due to the rotary powerof the transmitting medium preceding the guide l or contained in saidguide, the invention provides for the appli-cation of any known means.

According to a second form of execution of the invention, any phaseshifting correction may be rendered useless by generating thecontrolling voltage for the antifading after detection of the modulationat low frequency.

By Way of example, and by no means in a limiting sense, said form ofexecution is illustrated in Fig. 2, wherein the same symbols designatethe same elements, l2 designating the low frequency amplifier.

Although in the above description only antennae have been consideredthat form probes inside the guiding member, the invention is by notmeans limited to such arrangements. In particular, the wave collectingmembers may be located directly in the outer space or even belong to themost general systems of antenna screens.

What I claim is:

1. Apparatus for the reception of ultra short waves consisting of twohigh frequency waves rectilinearly polarized in planes at right anglesto one another and amplitude modulated in a manner such that the maximumvalues of one wave correspond to the minimum values of the other, thecombination of means for producing high frequency voltages, one fromeach of the modulated high frequency waves, means for changing thefrequency of said high frequency voltages, a variable gain amplifier foramplifying said voltages of changed frequency, means for detecting saidlast mentioned voltages, a circuit for adding said detected voltages andconnections for applying said added voltages to control theamplification of said variable gain amplifier substantially tocompensate for fading effects in said ultra short waves.

2. Apparatus for the reception of ultra short waves consisting of two=high frequency -waves rectilinearly polarized in planes yat rightangles to one another and amplitude modulated in a manner such that themaximum values of one wave correspond to the minimum values of theother, the combination of a Wave guide for said ultra short waves,pickup devices positioned in said wave guide for separately picking upsaid polarized ultra short waves, a pair of frequency changers connectedto said pickup devices respectively, `an oscillator connected to saidpair of frequency changers whereby the frequency of said ultra shortwaves is reduced in said frequency changers, a pair of variable gainamplifiers connected to said respective frequency changers, rectifiermeans and a, low time constant circuit connected in series to theoutputs of both of said pair of amplifiers and connections forconnecting the voltage developed across said low time lconstant circuitto control the amplification of said variable gain amplifierssubstantially to compensate for fading effects in said ultra shortwaves.

3. Apparatus for the reception of ultra short Waves as set forth inclaim 2 wherein said rectifier means consists of a pair of rectifiersconnected to the outputs of said variable gain amplifiers respectivelyand said relatively low time constant circuit consists of a resistorconnected between said rectifiers so that the outputs of said rectifiersare impressed in series across said resistor.

4. Apparatus as set forth in claim 2 further comprising a pair oftransformers connected to the outputs of said variable gain amplifiers,said transformers having secondaries connected in series to saidrectifier means, said relatively low time constant circuit includingapotentiometer having a variable contact connected to the commonconnection of said transformer secondaries so that the voltage developedacross the resistor of said potentiometer due to the signals receivedover said separate pickup devices may be made A substantially equal inabsolute value.

5. In apparatus for the reception of ultra short waves the combinationof a pair of receiving devices for separately receiving two highfrequency waves rectilinearly polarized in planes at right angles to oneanother and amplitude modulated in a manner such that the maximum valuesof one Wave correspond to the minimum values of the other, means forchanging the frequency of high frequency signals received, variable gainamplifier means for amplifying said signals of changed frequency, meansfor detectingV said signals, a circuit for adjusting the absolute valuesof the voltages derived from said detected signals to be substantiallyequal and for adding said detected voltages and connections for applyingsaid added voltages to control the amplification of said variable gainamplifier means substantially to compensate for fading effects in saidultra short Waves.

6. In apparatus for the reception of ultra short waves same two highfrequency waves rectilinearly polarized in planes at right angles to oneanother and amplitude modulated in a manner such that the maximum valuesof one wave correspond to the minimum values of the other, means forchanging the frequency of high frequency signals received, variable gainamplifier means for amplifying said signals of changed frequency, meansfor detecting said signals, transformer means coupled to said amplifiermeans, said transformer means having a pair of secondaries connected inseries, a pair of rectifiers connected to said secpotentiometer, saidpotentiometer having a v variable contact connected to the common con-jnection of said secundarios for adjusting the magnitude of the voltagesobtained from each of said secondaries, and connections for applyingsaid added voltages to control the amplification of said variable gainamplifier substantially to compensate for fading effects in said ultrashort waves.

GEORGES ROBERT PIERRE MARI.

REFERENCES CITED The following references are of record in the file ofthis patent:

Number Number 6 UNITED STATES PATENTS Name Date Runge Dec. 27, 1932Salinger June 6, 1944 Katzin Nov. 14, 1944 Busignies Aug. 26, 1947Blodget June 22. 1948 FOREIGN PATENTS Country Date Great Britain Oct.22, 1940

